VOYE V009B Home Music Remote Control Wireless Doorbell with 38 Polyphony Sounds, US Plug (White) 1. Simple humanized design, no need to ask for help from professionals or installers, completely exempt the decoration expenses, avoid chiseling the wall, insert it into the conventional socket in the room, and freely move the installation position. 2. The use of wireless high-frequency transmission technology, innovative intra-frequency code and dialing function, effectively avoiding the mutual interference between neighbors and the trouble caused by mistakes. 3. The effect of obstacles is much better than similar products in the industry, and can meet the needs of different family environments. 4. The transmitter has a signature card indication function, and has a groove and a protective cover designed to place the owners signature card. 5. The receiver has an ultrasonic mosquito repellent function, which truly realizes a multi-purpose machine. The receiver adopts fashionable streamline design and sandblasted craft multicolor optional decorative strips. 6. The use of constant voltage circuit design achieves a high-efficiency energy-saving effect and effectively increases the service life by more than 50%. 7. It can be used normally for more than one year (no laboratory press, 30 times a day). 8. The use of wireless doorbells is affected by environmental factors such as electromagnetic interference, installation on closed iron gates, occurrence of shielding, weather and humidity conditions, and the lack of timely battery replacement. 9. Extensive use, in addition to ordinary doorbells, it can also be used for special purposes such as contact, paging, patient care, and emergency notifications. 10. Receiver operating voltage: 200-240V 11. Power: =80m (open area) 14. Transmitter operating voltage: 12V (battery model: 23A 12V) 15. Transmitter operating current